Valve systems and injector system including such valve systems

ABSTRACT

A valve system for use in a system including a first source of a first pressurized fluid and a second source of a second pressurized fluid includes a valve housing including a first inlet port adapted to be placed in fluid connection with the first source, a second inlet port adapted to be placed in fluid connection with the second source and an outlet port. The valve system further includes a backflow prevention system to prevent flow of the first pressurized fluid through the second inlet and to prevent flow of the second pressurized fluid through the first inlet port. The valve system is adapted to provide a fluid path between at least the first inlet port and the outlet port to enable fluid to be drawn from the outlet port to the first inlet port. Several of the valve systems of the present invention provide for flow from the first inlet port to the outlet port and concurrent flow from the second inlet port to the outlet port.

BACKGROUND OF THE INVENTION

The present invention relates generally to valve systems and injectorsystems including such valve systems and, particularly, to valve systemsfor use in injecting multiple fluids and to injectors systems includingsuch valve systems.

In many medical procedures, such as drug delivery, it is desirable toinject a fluid into a patient. Likewise, numerous types of contrastmedia (often referred to simply as contrast) are injected into a patientfor many diagnostic and therapeutic imaging procedures. For example,contrast media are used in diagnostic procedures such as X-rayprocedures (including, for example, angiography, venography andurography), computed tomography (CT) scanning, magnetic resonanceimaging (MRI), and ultrasonic imaging. Contrast media are also usedduring therapeutic procedures, including, for example, angioplasty andother interventional radiological procedures. Regardless of the type ofprocedure, any fluid injected into the patient must be sterile andcontain a minimum of pyrogens.

A number of injector-actuated syringes and powered injectors for use inmedical procedures such as angiography, computed tomography, ultrasoundand NMR/MRI have been developed. U.S. Pat. No. 4,006,736, for example,discloses an injector and syringe for injecting fluid into the vascularsystem of a human being or an animal. Typically, such injectors comprisedrive members such as pistons that connect to a syringe plunger. Forexample, U.S. Pat. No. 4,677,980, the disclosure of which isincorporated herein by reference, discloses an angiographic injector andsyringe wherein the drive member of the injector can be connected to, ordisconnected from, the syringe plunger at any point along the travelpath of the plunger via a releasable mechanism. A front-loading syringeand injector system is also disclosed in U.S. Pat. No. 5,383,858, thedisclosure of which is incorporated herein by reference.

As illustrated in FIG. 1, in several currently available injectorsystems (see, for example, U.S. Pat. No. 5,494,036 and Published U.S.Patent Application No. US 2004-0064041) an injector 10 includes twosyringe interfaces 20 a and 20 b to which two syringes 50 a and 50 b areremovably attachable. Injector 10 includes two drive members or pistons30 a and 30 b which are operable to drive plungers 60 a and 60 b topressurize fluid within the syringes so that two different fluids can beinjected sequentially or simultaneously. For example, syringe 50 a cancontain a contrast medium and syringe 50 b can contain a diluent orother medical fluid such as saline. As illustrated in FIG. 1, aT-connector 70 is typically provided to connect the fluid paths fromeach of syringes 50 a and 50 b to a fluid path connected to the patient.Check valves 80 a and 80 b can be provided to ensure that fluid cannotflow into either of syringe 50 a and syringe 50 b, respectively, via thefluid set attached to the syringes. As an alternative to a T-connector,a stopcock can be provided with check valves as described above.Unfortunately, these configurations add cost and only address parts of aneeded device for these types of power injection systems. For example acheck valve provides directional flow to prevent backflow however itdoes not provide the ability to perform a patency check. In a patencycheck, the plunger of one of the syringes in fluid connection with thepatient is drawn rearward to check if blood is drawn into the fluidpath. Drawing blood into the fluid path provides an indication that acatheter on the end of the patient fluid path is appropriately within ablood vessel.

It is desirable to develop improved devices, systems and method for usein connection with injector systems to reduce or eliminate the above andother problems associated with current injection systems while keepingcost of goods in check

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a valve system for use ina system including a first source of a first pressurized fluid and asecond source of a second pressurized fluid. The valve system includes avalve housing including a first inlet port adapted to be placed in fluidconnection with the first source, a second inlet port adapted to beplaced in fluid connection with the second source and an outlet port.The valve system further includes a backflow prevention system toprevent flow of the first pressurized fluid through the second inlet andto prevent flow of the second pressurized fluid through the first inletport. The valve system is adapted to provide a fluid path between atleast the first inlet port and the outlet port to enable fluid to bedrawn from the outlet port to the first inlet port. Several of the valvesystems of the present invention provide for flow from the first inletport to the outlet port and concurrent flow from the second inlet portto the outlet port.

In several embodiments, the valve system can also include a bypass flowpath to direct flow around the second check valve, thereby providing afluid path between the outlet port and the second inlet port to enablefluid to be drawn from the outlet port to the second inlet port.

The backflow prevention system can, for example, include a first checkvalve in fluid connection with the first inlet port and a second checkvalve in fluid connection with the second inlet port. The valve systemcan further include a bypass flow path to direct flow around the firstcheck valve, thereby providing the fluid path between the outlet portand the first inlet port to enable fluid to be drawn from the outletport to the first inlet port.

The backflow prevention system can include a sealing member movablewithin the valve housing in response to pressure changes. The sealingmember can have a normal state in which it is biased to block flow intothe second inlet port, while a fluid path between the first inlet portand the outlet port is provided to enable fluid to be drawn from theoutlet port to the first inlet port. The at least one sealing membercan, for example, be biased by at least a first spring.

In one embodiment, the sealing member includes a piston member biased toabut a portion of the valve housing to block flow into the second inletport. The piston has a passage therethrough in fluid connection with theoutlet. The valve system can further include a valve housing memberhaving a passage therethrough in fluid connection with the first inletport. The first check valve in this embodiment can be in fluidconnection with the passage in the valve housing member. The passage inthe piston can be in fluid connection with the passage in the valvehousing member. A fluid path can be provided around the housing memberto provide the bypass flow path in fluid connection with the passage inthe piston and the first inlet port when the piston is biased to abutthe portion of the valve housing. Flow from the second fluid path cancause the piston to move out of abutment with the portion of the valvehousing to provide a fluid connection between the second inlet port andthe outlet port. The piston can be moved to abut the valve housingmember to block the bypass flow path, while the passage in the pistonremains in fluid connection with the passage in the valve housingmember.

In several embodiments of the valve systems of the present invention,the backflow prevention system can include at least a first sealingmember movable within the valve housing in response to pressure changes.The first sealing member can, for example, be biased to provide thefluid path between the first inlet port and the outlet port. The firstsealing member can, for example, be biased by a first spring.

Flow from the second inlet port can cause movement of the first sealingmember to block the fluid path between the first inlet port and theoutlet port.

The valve system can also include a second sealing member moveablewithin the valve housing and a second spring positioned between thefirst sealing member and the second sealing member. Flow from the firstinlet and concurrent flow from the second inlet causes the second springto compress so that a fluid path is provided between the first inletport and the outlet port and a fluid path is provided between the secondinlet port and the outlet port.

In several other embodiment of the present invention, the backflowprevention system includes a deformable sealing member biased to blockflow into the second inlet port. Flow of fluid into the second inletport at a first pressure can, for example, deform a first portion of thesealing member to block flow into the first inlet port. Flow of fluidinto the second inlet port at a second pressure higher than the firstpressure can deform a second portion of the sealing member to open afluid path between the second inlet port and the outlet port.

The valve housing can include a first housing member (for example,including the first inlet) and a second housing member (for example,including the second inlet port). The first housing member and thesecond housing member can be attached to form the valve housing, whereinthe deformable sealing member is positioned between the first housingmember and the second housing member. A fluid path can be providedbetween the first inlet port and the outlet port regardless of a stateof the deformable sealing member. Flow into the first inlet port andconcurrent flow into the second inlet port can cause flow from the firstinlet port into the outlet port and concurrent flow from the secondinlet port into the outlet port.

The backflow prevention system can also include a flexible conduitpositioned within the valve housing to block the second inlet port frombeing in fluid connection with the outlet port. A passage through theconduit can provide the fluid path between the first inlet port and theoutlet port to enable fluid to be drawn from the outlet port to thefirst inlet port. An increase in pressure in the second inlet port canresult in compression of a first portion of the flexible conduit toclose the fluid path between the first inlet port and the outlet port. Afurther increase in pressure in the second inlet port can cause a secondportion of the flexible conduit to compress to create a fluid pathbetween the second inlet port and the outlet port.

In another aspect, the present invention provides an injection systemincluding: a first source of a first pressurized fluid; a second sourceof a second pressurized fluid, and a valve system as described above. Inthat regard, the valve system can include a valve housing including afirst inlet port in fluid connection with the first source, a secondinlet port in fluid connection with the second source and an outletport. The valve system further includes a backflow prevention system toprevent flow of the first pressurized fluid through the second inlet andto prevent flow of the second pressurized fluid through the first inletport. The valve system is adapted to provide a fluid path between atleast the first inlet port and the outlet port to enable fluid to bedrawn from the outlet port to the first inlet port. The first sourcecan, for example, be a first syringe in fluid connection with a poweredinjector, and the second source can for example, be a second syringe influid connection with the powered injector.

In a further aspect, the present invention provides a valve system foruse in a system including a first source of a first pressurized fluidand a second source of a second pressurized fluid. The valve systemincludes: a valve housing including a first inlet port adapted to beplaced in fluid connection with the first source, a second inlet portadapted to be placed in fluid connection with the second source and anoutlet port; at least one deformable sealing member in operativeconnection with the first inlet port and the second inlet port, the atleast one deformable sealing member being biased to block flow into thesecond inlet port, and a fluid path between the first inlet port and theoutlet port regardless of a state of the deformable sealing member. Flowof fluid into the second inlet port at a first pressure deforms acentral portion of the sealing member to block flow into the first inletport. Flow of fluid into the second inlet port at a second pressure,higher than the first pressure, deforms an outer portion of the sealingmember to open a fluid path between the second inlet port and the outletport. Flow into the first inlet port and concurrent flow into the secondinlet port deforms the central portion of the deformable sealing memberand causes flow from the first inlet port into the outlet port andconcurrent flow from the second inlet port into the outlet port. In oneembodiment, the valve housing includes a first housing member includingthe first inlet and a second housing member including the second inletport. The first housing member and the second housing member can beattached to form the valve housing. The deformable sealing member ispositioned between the first housing member and the second housingmember. The outlet can, for example, be formed in one of the firsthousing member or the second housing member. The outlet port can also beformed upon attachment of the first housing member and the secondhousing member. In general, the housing can include two housing membersthat are attachable to form a housing including the first inlet, thesecond inlet port and the outlet port. Preferably, the at least onedeformable sealing member is positionable between the housing membersduring assembly to provide for efficient and cost effective assembly.

The present invention also provide methods of delivering fluids usingthe above devices and systems.

In several embodiments, the present invention thus provides devices,systems and methods to provide input isolation to prevent backflow intofluid sources prior to coupling (that is, providing fluid connectionbetween) one of the input ports of a valve system to the output portthereof. Moreover, the devices, systems and methods of the presentinvention provide also provide for checking for patency through at leastone input ports of the valve system. In several embodiments, thedevices, systems and methods of the present invention also provide forconcurrent or dual flow through both of the input ports to the outputport without user intervention.

The present invention, along with the attributes and attendantadvantages thereof, will best be appreciated and understood in view ofthe following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a currently available injectorsystem including two syringes in which the outflow of each syringe isconnected to a patient fluid path via a T-connector, and wherein checkvalves are provided to prevent backflow into the syringes.

FIG. 2A illustrates an embodiment of an injector system of the presentinvention including an embodiment of a valve system of the presentinvention.

FIG. 2B illustrates a cross-sectional view of the valve system of FIG.2A.

FIG. 2C illustrates another cross-sectional view of the valve system ofFIG. 2B.

FIG. 2D illustrates a side view of the valve system of FIG. 2B.

FIG. 2E illustrates a cutaway view of the valve system of FIG. 2B.

FIG. 3A illustrates a perspective view of another embodiment of a valvesystem of the present invention for use in connection with an injectorsystem as, for example, illustrated in FIG. 2A.

FIG. 3B illustrates a cross-sectional view of the valve system of FIG.3A wherein an integral three-way stopcock valve is set to open a fluidpath between a source of a first fluid and an outlet of the valvesystem.

FIG. 3C illustrates a cross-sectional view of the valve system of FIG.3A wherein an integral three-way stopcock valve is set to open a fluidpath between the source of the first fluid and a source of a secondfluid and the outlet of the valve system.

FIG. 4A illustrates another embodiment of an injector system of thepresent invention including valve systems which permit flow without thereverse mixing.

FIG. 4B illustrates an enlarged cross-sectional view of the valvesystems of the injector system of FIG. 4A.

FIG. 5A illustrates another embodiment of a valve system of the presentinvention wherein a plug member is slidably disposed within the valvehousing.

FIG. 5B illustrates the valve system of FIG. 5A wherein the plug memberis positioned to provide fluid connection between a first fluid sourceand an outlet port and to block fluid connection between a second fluidsource and the outlet port.

FIG. 5C illustrates the valve system of FIG. 5A in which the plug memberis positioned to provide fluid connection between the second fluidsource and the outlet port and to block fluid connection between thefirst fluid source and the outlet port.

FIG. 6A illustrates another embodiment of a valve system of the presentinvention in which the plug member is biased in a position to providefluid connection between a first fluid source and an outlet port whilepreventing fluid connection between a second fluid source and the outletport.

FIG. 6B illustrates the valve system of FIG. 6A in which pressurizedflow from the second fluid source moves the plug member to a position toprovide fluid connection between the second fluid source and the outletport while preventing fluid connection between the first fluid sourceand the outlet port.

FIG. 7A illustrates another embodiment of an injector system of thepresent invention including a dual shuttle valve system in which theshuttle or plug members are biased in a normal position to provide fluidconnection between a second source of fluid and an outlet port, whileclosing fluid connection between the first source of fluid and theoutlet port.

FIG. 7B illustrates the dual shuttle valve of FIG. 7A wherein the plugmembers are in a position to close the fluid path between the secondfluid source and the outlet port and close the fluid path between thefirst fluid source and the outlet port.

FIG. 7C illustrates the dual shuttle valve of FIG. 7A wherein the plugmembers are in a position to close the fluid path between the secondfluid source and the outlet port and open the fluid path between thefirst fluid source and the outlet port.

FIG. 7D illustrates the dual shuttle valve of FIG. 7A wherein the plugmembers are in a position to open the fluid path between the secondfluid source and the outlet port and open the fluid path between thefirst fluid source and the outlet port, thereby allowing simultaneousflow from the first fluid source and the second fluid source to theoutlet port.

FIG. 8A illustrates another embodiment of an injector system of thepresent invention including a valve system to control fluid connectionsbetween two sources of fluid and an outlet port.

FIG. 8B illustrates valve system of FIG. 8A in a state to prevent fluidflow from either source of fluid.

FIG. 8C illustrates the valve system of FIG. 8A in a state permittingflow from the first fluid source to the outlet port, while preventingfluid flow from the second fluid source to the outlet port.

FIG. 8D illustrates the valve system of FIG. 8A in a state permittingsimultaneous flow and mixing from both fluid sources.

FIG. 9A illustrates another embodiment of a valve system of the presentinvention.

FIG. 9B illustrates the valve system of FIG. 9A in a state permittingflow from a first inlet port to an outlet port while preventing flowfrom a second inlet port to the outlet port.

FIG. 9C illustrates the valve system of FIG. 9A wherein pressure fromthe second inlet port closes the fluid path between the first inlet portand the outlet port.

FIG. 9D illustrates the valve system of FIG. 9A in a state permittingflow from the second inlet port.

FIG. 9E illustrates a side view of the flexible diaphragm of the valvesystem of FIG. 9A.

FIG. 9F illustrates the valve system of FIG. 9A in a state permittingsimultaneous flow an mixing from both the first inlet port and thesecond inlet port.

FIG. 9G illustrates the valve system of FIG. 9A in a disassembled state.

FIG. 10A illustrates an embodiment of a valve system of the presentinvention in a normal state providing fluid connection between a firstinlet port and an outlet port.

FIG. 10B illustrates the valve system of FIG. 10A in a state preventingflow from either the first or second inlet port to the outlet port.

FIG. 10C illustrates the valve system of FIG. 10A in a state permittingflow from the second inlet port to the outlet port.

FIG. 10D illustrates the valve system of FIG. 10A in a state permittingsimultaneous flow and mixing from both inlet ports.

FIG. 11A illustrates another embodiment of a valve system of the presentinvention in a state to permit fluid connection between a second inletport and an outlet port.

FIG. 11B illustrates the valve system of FIG. 11A in a state preventingflow from either the first or second inlet port to the outlet port.

FIG. 11C illustrates the valve system of FIG. 11A in a state permittingflow from the second inlet port to the outlet port.

FIG. 11D illustrates the valve system of FIG. 11A in a state to permitsimultaneous flow and mixing from both inlet ports.

FIG. 11E illustrates the valve system of FIG. 11A in a disassembledstate.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2A illustrates an embodiment of an injector system of the presentinvention in which an injector 10 includes two syringe interfaces 20 aand 20 b to which two syringes 50 a and 50 b are attachable. Asdiscussed in connection with FIG. 1, injector 10 includes two drivemembers or injector pistons 30 a and 30 b which are operable to driveplungers 60 a and 60 b to pressurize fluid within syringes 50 a and 50b, respectively, so that two different fluids can be injectedsequentially or simultaneously. For example, syringe 50 a can contain acontrast medium and syringe 50 b can contain a diluent such as saline oranother medical fluid. As also illustrated in FIG. 2A, an automatic dualflow, anti-mixing valve system 100 is provided to connect fluid paths120 a from each of syringes 50 a and 50 b, respectively, to a fluid path120 c connected to the patient.

As illustrated in FIGS. 2B through 2E, valve 100 includes a first valvebody 106 and second valve body 108 which can, for example, bepermanently attached to form a valve housing 110. Valve housing 110includes two inlet ports 114 a and 114 b and an outlet port 114 c. Inletport 114 a is connected to fluid path 120 a (for example, flexibletubing) which provides for fluid connection between syringe 50 a andvalve 100. Similarly, inlet port 114 b is connected to fluid path 120 b(for example, flexible tubing) which provides for fluid connectionbetween syringe 50 b and valve 100 and allows fluid from syringe 50 b toflow axially through a bore or passage 140 a in a valve piston 140 tooutlet port 114 c. Valve piston 140 is able to move axially within valvehousing 110. Valve piston 140 is normally biased upward (for example,via a spring 122 a) against the top (in the orientation of FIG. 2B)inside surface of valve housing 110. In the normal position or state, anannular clearance 144, which is in fluid connection, with inlet port 114a is blocked from fluid connection with outlet port 114 c by the contactof valve piston 140 with the interior surface of housing 110. Fluidpressure from inlet port 114 a applies force on an angled top surface144 of the valve piston 140, and causes the valve piston 140 to movedownward, compressing spring 122 a and providing for fluid connectionbetween inlet port 114 a and outlet port 114 c (see FIG. 2E).

Valve 100 has four distinct operating modes. In a first mode, only fluidfrom syringe 50 b (for example, saline) can be injected. In thisoperating mode, flow from syringe 50 a is prevented. As described above,spring 122 a normally maintains the valve piston 140 in the extended(raised) or normal position as illustrated in FIG. 1A. As the injector'spiston 30 b is extended, fluid is forced to flow from syringe 50 b,through fluid path 120 b and into bore 140 (via inlet 114 b). Fluid fromsyringe 50 b can flow thorough a first one-way check valve 130 in fluidconnection with bore 140 a and on to the patient. It is also possiblefor fluid from syringe 50 b to flow through an annular space 156 betweenvalve housing 110 and housing member 152 and through a space 154 betweenhousing member 152 and piston 144, to enter center bore 140 a of thevalve piston 140 and on to the patient. Flow will normally occur throughboth of these fluid paths in parallel. Because both fluid pressure andthe return spring 122 a keep the valve piston 140 in its extended(raised) position, it is not possible for the fluid from syringe 50 b toflow into syringe 50 a. A second check valve 132 further precludes flowfrom the syringe 50 b into syringe 50 a.

In a second mode, only fluid form syringe 50 a can be injected. Fluidflows from syringe 50 b into inlet 114 a via fluid path 120 a and passesthrough second one-way check valve 132. The pressure of fluid fromsyringe 50 a applies force to top surface 144 of valve piston 140,forcing valve piston 140 downward until the lower surface (in theorientation of FIGS. 2B and 2E) of the valve piston 140 abuts againsthousing member 152 (see FIG. 2E). Return spring 122 a is compressed asvalve piston 140 is forced downward. As valve piston 140 moves downward,a fluid connection is formed between outlet port 114 c and annularclearance or volume 148. This fluid connection allows contrast to flowfrom inlet port 114 a to outlet port 114 c and therethrough to fluidpath 120 c and to the patient. Check valve 130 prevents fluid fromflowing from the syringe 50 a into syringe 50 b via bore 140 a.

In a third mode of operation, fluid from both syringe 50 a and syringe50 b can be simultaneously injected. Fluid flows from syringe 50 a andpasses through volume 148 and outlet port 114 c as described above. Asalso described above, fluid flows from syringe 50 b and passes throughcheck valve 130, through center bore 140 a of valve piston 140, and onto the patient. It is possible, and desirable, for fluids from syringe50 a and 50 b (for example, contrast and saline) to mix together in, forexample, annular clearance or volume 148. Check valve 130 preventssaline from flowing into syringe 50 b, and check valve 13 e preventscontrast from flowing into syringe 50 a.

In a fourth mode of operation, a patency check can be performed. Asthere is no flow from syringe 50 a, return spring 122 a maintains valvepiston 140 in the extended (raised) position as illustrated in FIG. 2Bduring the entire patency check process. Annular space or volume 152 isin fluid connection with center bore 140 a of the valve piston 140 (andtherethrough with outlet 114 c and the patient) in this valve state. Inthis state, retraction of injector piston 30 b (and, thereby, retractionof plunger 60 b of syringe 50 b) causes fluid to be drawn from thepatient (via the fluid connection between center bore 140 a, annularspace 152 and inlet port 114 b, which provides a bypass around/of checkvalve 130).

FIGS. 3A-3C illustrate another embodiment of a valve system 200 of thepresent invention. Valve 200 includes a housing 210, which includes afirst inlet port 214 a that can, for example, be placed in fluidconnection with syringe 50 a via, for example, fluid path 120 a. Asecond inlet port 214 b of housing 210 can, for example, be placed influid connection with syringe 50 b via, for example, fluid path 120 b.Housing 210 also includes an outlet port 214 c which can be placed influid connection with a patient via, for example, fluid path 120 c. Abypass fluid path 252 is in fluid connection between inlet port 214 band a bypass port 254 of housing 210.

Rotatably disposed within housing 210 is a three-way stop cock valvemember 240 (see FIGS. 3B and 3C). A connector 246 (see FIG. 3A) isprovided to effect either manual control or automated control (forexample, via servos or other actuators as known in the art) of the stateor position of valve member 240 and, thereby, the state of valve system200. A first state of valve system 200 is illustrated in FIG. 3B inwhich inlet port 214 b and bypass port 254 are place in fluid connectionwith outlet port 214 c. In this state, fluid can be injected into thepatient via, for example, syringe 50 b or other pressurizing device influid connection with inlet port 214 b. As no fluid connection isprovided between inlet port 214 b and inlet port 214 a in this state, nofluid can enter, for example, syringe 50 a in fluid connection withinlet port 124 a. Further, a patency check can be performed in the valvestate of FIG. 3A by, for example, retracting plunger 60 b of syringe 50b in fluid connection with inlet port 214 b.

In another valve state illustrated in FIG. 3C, fluid connection isprovided between each of inlet port 214 a and inlet port 214 b andoutlet port 214 c. Fluid can thus be injected into the patient viaeither inlet port 214 a or inlet port 214 b. One-way check valve 230prevents fluid from exiting valve system 200 via inlet port 214 b, whileone-way check valve 232 prevents fluid from exiting valve system 200 viainlet port 214 a (thereby preventing backmixing in, for example,syringes 50 a and 50 b). Simultaneous flow of fluid to the patient fromboth inlet ports 214 a and 214 b can also be effected in the valve stateof FIG. 3C.

In another embodiment of an injection system of the present invention asillustrated in FIGS. 4A and 4B, a valve system 400 includes first andsecond actuatable (for example, push-button) valves 420 a and 420 bwhich allow an operator (either manually or automatically) to accessfluids from either or both of reservoirs 410 a and 410 b (for example,syringes). One way check valves 430 a and 430 b prevent reverse mixingor backflow of fluids into reservoirs 410 a and 410 b. First reservoir410 a can, for example, be a container or syringe for contrast fluids,while second reservoir 410 b can be a container or syringe for saline.First and second actuatable valves 420 a and 420 b are normally in aclosed position. Examples of such valves are known in the valve arts astrumpet valves. First and second actuators or push buttons 440 a and 440b are manually or automatically activatable by an operator to open firstor second valves 420 a and 420 b, to open a fluid path between reservoir400 a or 400 b, respectively, and outlet 450 to provide for a patencycheck or to provide for refilling. Check valves 430 a and 430 b allowfluid to flow from reservoir 410 a and/or 410 b, but prevent flow intoreservoirs 410 a and 410 b, respectively. A common outlet port 450delivers fluid from either or both of first and second reservoirs 410 aand 410 b to the patient.

If first reservoir 410 a is pressurized, check valve 430 a opens andallows fluid flow to outlet port 450. However, fluid cannot flowbackwards through check valve 430 b into second reservoir 410 b. Ifsecond reservoir 410 b is pressurized, check valve 430 b opens andallows flow to outlet port 450. However, fluid cannot flow backwardsthrough first check valve 430 a into first reservoir 410 a. If bothreservoirs 410 a and 410 b are pressurized, check valves 430 a and 430 bopen and allow the fluids to flow to outlet port 450. Mixing can onlytake place downstream of check valves 430 a and 430 b.

FIG. 4B provides an enlarged view of valves 420 a and 420 b showingsecond valve 420 b opened by actuation of button 440 b, while firstvalve 420 a is in a closed state. First and second actuatable valves 420a and 420 b are provided so that an operator can selectively bypassfirst and second check valves 430 a or 430 b so fluid can be moved ineither direction through these valves. This can be done to perform apatency check or to refill reservoirs 410 a and 410 b.

FIGS. 5A-5C illustrate another embodiment of a valve 500 of the presentinvention including a housing 510 in which a moveable plug, shuttle orsealing member 540 is slidably disposed. Housing 510 includes a firstinlet port 514 a, a second inlet port 514 b and an outlet port 514 c. InFIG. 5A, plug member 540 is illustrated in an arbitrary or neutralstarting position. In FIG. 5B, pressurized fluid from, for example, asyringe in fluid connection with second inlet port 514 b causes plugmember to slide to the left or toward first inlet port 514 a so thatsecond inlet port 514 b is placed in fluid connection with outlet port514 c. Plug member 540 blocks first inlet port 514 a from fluidconnection with second inlet port 514 b and outlet 514 c, preventingflow of fluid from second inlet port 514 b into first inlet port 514 a.In the position or state illustrated in FIG. 5B, fluid can flow to (forexample, for a patency check) or from inlet port 514B. In FIG. 5C,pressurized fluid from, for example, a syringe in fluid connection withfirst inlet port 514 a causes plug member 540 to slide to the right ortoward second inlet port 514 b so that first inlet port 514 a is placedin fluid connection with outlet port 514 c. Plug member 540 blockssecond inlet port 514 b from fluid connection with first inlet port 514a and outlet 514 c, preventing flow of fluid from first inlet port 514 ainto inlet second port 514 b. In the position or state illustrated inFIG. 5C, fluid can flow to or from inlet port 514 c.

FIGS. 6A and 6B illustrate another embodiment of a valve 600 of thepresent invention which includes a valve housing 610. Valve housingincludes a first inlet port 614 a, a second inlet port 614 b and anoutlet port 614 c. A plug, shuttle or sealing member 640 is slidablypositioned within housing 610. In this embodiment plug member, is biased(for example, via spring 622) in the state or position illustrated inFIG. 6A in which first inlet port 614 a is in fluid connection withoutlet port 614 c. In this position, second fluid port 614 b is blockedfrom fluid connection with first inlet port 614 a and with outlet port614 c. In the state of FIG. 6A pressurized fluid entering first inletport 614 a can flow out of outlet port 614 c to a patient, while flow offluid from first inlet port 614 a through second inlet port 614 b isprevented. Also in this state, a patency check can be performed via, forexample, a syringe in fluid connection with first inlet port 614 a. InFIG. 6B, pressurized fluid entering valve 600 via second inlet port 614b overcomes the force of spring 622, causing plug member 640 to movetoward first inlet port 614 a. Fluid connection between first fluid port614 a and either outlet port 614 c or second inlet port 614 b is blockedbefore any fluid from second inlet port 614 b can exit outlet port 614c.

FIG. 7A illustrates an embodiment of an injection system of the presentinvention including a dual shuttle valve 700 to control flow from twofluid sources or reservoirs 710 a and 710 b. Valve 700 allows reverseflow to one reservoir to, for example, provide for a patency check, butprevents mixing between reservoirs 710 a and 710 b. Valve 700 furtherallows flow from either or both of reservoirs 710 a and 710 b asdesired. The valve body or housing 720 includes a first inlet port 724a, a second inlet port 724 b and an outlet port 724 c. Valve housing 720further includes a first plug, shuttle or sealing member 730 amoveably/slidably disposed therein and a second plug, shuttle or sealingmember 730 b moveably/slidably disposed therein. A first biasing spring740 a is positioned between first plug member 730 a and second plugmember 730 b, and a second biasing spring 740 b is disposed betweensecond plug member 730 b and a second inlet side of valve housing 720.

First plug member 730 a is slideable in valve housing 720 to controlflow between first reservoir 710 a and outlet port 724 c. Second plugmember 730 b is slideable in valve body 720 to control flow from secondreservoir 710 b to outlet port 724 c. First biasing spring 740 aprimarily positions first shuttle 730 a inside valve body 720. Secondbiasing spring controls the position of both first and second plugmember 730 a and 730 b. Outlet port 724 c delivers fluid from firstand/or second fluid reservoir 710 a and 710 b to a patient undertreatment.

In FIG. 7A, valve housing 720 is illustrated in the “normal” position orstate. In this state, reservoir 710 a is shut off from delivering fluidas first biasing spring 740 a has biased first plug member 730 a into aposition blocking the fluid path to outlet port 724 c. However,reservoir 710 b is allowed to deliver fluid to outlet port 724 c assecond plug member 730 b is biased by the second biasing spring 740 b sothat second reservoir 710 b is in fluid connection with outlet 750. Inthis normal position, fluid can flow in either direction through valvebody 720 (that is, from inlet port 724 b to outlet port 724 c or inreverse, providing, for example, for fluid delivery from secondreservoir 710 b, filling of second reservoir 710 b or a patency check).

In FIG. 7B, fluid in first reservoir 710 a is pressurized. As thepressure from reservoir 710 a increases, force on first plug member 730a causes first biasing spring 740 a to compress slightly, which pushessecond plug member 730 b toward second inlet port 724 b and, in turn,compresses second biasing spring 740 b. As this occurs, second plugmember 730 b closes the fluid path from reservoir 710 b to outlet port724 c before the fluid path between first reservoir 710 a and outletport 724 c is opened.

As illustrated in FIG. 7C, as the pressure in reservoir 710 a increasesfurther, first biasing spring 740 a is further compressed more by theforce upon first plug member 730 a, opening the fluid path between firstreservoir 710 a and outlet port 724 c and allowing the fluid in firstreservoir 710 a to flow to outlet port 724 c. However, the fluid pathbetween reservoir 710 b and outlet port 724 c remains closed.

In FIG. 7D, the pressure in reservoir 710 b is increased while flow ismaintained from reservoir 710 a. Second plug member 730 b is forced inthe direction of first inlet port 724 a, compressing first biasingspring 740 a. Second biasing spring 740 b is expanded to approximatelyits normal position, opening the fluid path between second reservoir 710b and outlet port 724 c and allowing flow from second reservoir 710 b tooutlet port 724 c. In the state illustrated in FIG. 7D, simultaneousflow and mixing occurs downstream, but backflow into and mixing withinreservoirs 710 a and 710 b is prevented.

FIG. 8A illustrates an embodiment of a fluid delivery or injectionsystem of the present invention including a spool and check valve system800 to connect two fluid reservoirs 810 a and 810 b (via, first inletport 824 a and second inlet port 824 b, respectively) to a common outletport 824 c. A spool valve assembly 830 is slideable within valve housing820, and forms a sealing engagement with valve housing 820 on theoutside diameter of spool valve assembly 830. In the normal position orstate as illustrated in FIG. 8A, the fluid path between second reservoir810 b and outlet port 824 c is in an open state to allow fluid to flowfrom second reservoir 810 b to outlet port 824 c. A spring 840 biasesspool valve assembly 830 into a position providing fluid connectionbetween second reservoir 810 b and outlet port 824 c, thereby providingfor flow from first reservoir 820 b and reverse flow to first reservoir820 b (for example, for filling or for a patency check). The fluid pathbetween second reservoir 810 a and outlet port 824 c is closed off by aspool or plug member 832 in spool valve assembly 830.

FIG. 8B illustrates that a pressure increase in reservoir 810 a (whilereservoir 810 b remains unpressurized) forces spool valve assembly 830toward second inlet port 824 b and collapses spring 840 slightly. Inthis position, the fluid path between first inlet port 824 a and outlet824 c is closed, while the fluid path between second fluid inlet 824 band outlet 824 c remains closed, and fluid cannot flow from eitherreservoir 810 a or 810 b to outlet port 824 c.

As illustrated in FIG. 8C, as the pressure is increased within firstreservoir 810 a, spool valve assembly 830 is forced further towardsecond inlet port 824 c, further collapsing spring 840, and opening thefluid path between first inlet port 824 a and outlet port 824 c, therebyconnecting fluid reservoir 810 a with outlet port 824 c. In the stateillustrated in FIG. 8C, the fluid path between second inlet port 824 band outlet port 824 c is closed by spool valve assembly 830 and fluidflow from reservoir 810 b remains blocked, thus preventing any mixing ofthe fluids from the reservoirs. A one-way check valve 850 furtherprevents flow from fluid reservoir 810 a into reservoir 810 b.

In FIG. 8D, both reservoirs 810 a and 810 b are pressurized. Fluid fromreservoir 810 a flows through valve housing 820 and spool valve assembly830 to outlet port 824 c. Fluid from reservoir 810 b forces one-waycheck valve 850 (for example, a ball check valve as known in the art) toopen, allowing fluid to flow to the outlet port 824 c. The stateillustrated in FIG. 8D permits the simultaneous flow of fluids from bothreservoirs 810 and 810 b. If flow stops from one of reservoirs 810 a or810 b, spool valve assembly 830 or check valve 850 operate as describedabove to automatically prevent any mixing between reservoirs 810 a and810 b.

FIGS. 9A-9F illustrate another embodiment of a valve system 900 of thepresent invention. In the illustrated embodiment, valve 900 includes afirst or right (in the orientation of FIGS. 9A through 9D) valve housing910 a and a second or left valve housing 910 b, which can, for example,be permanently connected. A flexible diaphragm 920 controls flow throughvalve system 900 in response to pressure from a first fluid (forexample, saline) entering a first inlet port 930 or a second fluid (forexample, a contrast medium) entering a second inlet port 940. Fluidexits valve system 900 via an exit port 970.

FIGS. 9A and 9B illustrate valve system 900 in its normal state. In thisstate, fluid can flow from a source of fluid in connection with firstinlet port 930 (for example, a syringe in fluid connection with firstfluid path 980 a), passing through an exit end 932 of inlet port 930 andthrough a passage 950 to outlet port 970 (see FIG. 9B). It is alsopossible to perform a patency check via second inlet port 940 in thenormal state.

In the normal state as, for example, illustrated in FIG. 9A, a centralportion 922 (see FIG. 9E and 9F) of flexible diaphragm 920 blocks anexit end 942 of second inlet port 940. A peripheral or outside portion924 (see FIGS. 9D and 9F) of flexible diaphragm 920 blocks an opening962 (see, for example, FIG. 9F) between second inlet port 940 and outletport 970. Fluid entering valve system 900 from first inlet port 930 isthus blocked from flowing to second inlet port 940 and therethrough toany fluid source or reservoir in fluid connection with second inlet port940.

As illustrated in FIG. 9C, pressurized fluid entering second inlet port940 via, for example, a second fluid path 980 b (for example, flexibletubing) supplies a second fluid (for example, contrast) to second inletport 940 and exerts pressure on a central portion 922 (see FIG. 9D) offlexible diaphragm 920. Central portion 922 of flexible diaphragmdeforms to block exit end 932 of first inlet port 930. A furtherincrease in pressure, results in deformation of peripheral portion 924of flexible diaphragm 920 as illustrated in FIG. 9D. Fluid entering,second fluid inlet 940 passes through passage 960 and passage 962 (seeFIGS. 9D and 9F) to outlet port 970. Preferably, the pressure requiredto deform central portion 922 to block exit end 932 of inlet port 930 isless than the pressure required to deform peripheral portion 924 to openpassage 962. Such an embodiment of flexible diaphragm 920 ensures thatfirst inlet port 930 will be blocked before fluid from second inlet port940 begins to flow through valve system 900, thereby ensuring thatbackmixing into first inlet port 930 is prevented. Diaphragm 920 can,for example, include a first material for central portion 922 and asecond material for peripheral portion 924 to provide for differentflexing forces/pressures. Alternatively, diaphragm 920 can be made of asingle material and the thickness of central portion 922 can be lessthan the thickness of peripheral or outer portion 924 to provide fordifferent flexing forces/pressures. Further, more than one flexiblesealing member or diaphragm can be used. Preferably, differentopening/flexing forces or pressures are provided ad described above. Useof a single flexible sealing member or diaphragm can, however, provideimproved assembly efficiencies.

FIG. 9F illustrates the valve system of FIG. 9A in a state permittingsimultaneous flow an mixing from both the first inlet port and thesecond inlet port. In general, the pressures in first inlet 980 a,second inlet 980 b and outlet 970 are approximately equal in the dualflow mode.

FIGS. 10A-10D illustrate another embodiment of a valve system 1000 ofthe present invention which is connectible to a first fluid source and asecond fluid source (for example, syringe 50 a and syringe 50 b), via afirst inlet port 1010 and a second inlet port 1060, respectively. Valvesystem 1000 includes a check valve (for example, a flexible elastomericdisk) 1020 to control the fluid connection between first inlet port 1010and outlet port 1070. A post 1030 biases flexible elastomeric disk 1020in a closed position in which it blocks an exit 1012 of a passageleading to first inlet port 1010. A flexible diaphragm valve 1040 isalso in fluid connection with first inlet port 1010. Flexible diaphragmvalve does not allow fluid to pass in either direction, but operates tocontrol the state of a passage 1050 in response to fluid pressure infirst inlet port 1010. Outlet port 1070 delivers fluid from either orboth of the inlet ports 1010 and/or 1060 to a patient.

In FIG. 10A, valve system 1000 is in its normal state, wherein fluid canflow from second inlet port 1060 to outlet port 1070 or from outlet port1070 to second inlet port 1060 (for example, to perform a patencycheck). Fluid cannot flow into the first inlet port 1010 from secondinlet port 1010 because elastomeric disk 1020 blocks end 1012 of inletport 1010. As illustrated in FIG. 10B, as the pressure in first inletport 1010 is increased, and at a pressure less than required to openelastomeric disk 1020 (for example, about 5 psi), diaphragm valve 1040deforms to close passage 1050. As illustrated in FIG. 10C, as thepressure in first inlet port 1010 increases above the pressure requireddeform/open elastomeric disk 1020 fluid can flow from first inlet port1010 to the outlet port 1070 (for example, this can occur at a pressuresgreater than 5 psi). In this state, no flow or mixing can take place insecond inlet port 1060 because diaphragm valve 1040 closes passage 1050.

In FIG. 10D, fluid pressure in second inlet port 1060 is also increased.As the pressure in inlet port 1060 is increased to match the fluidpressure in first inlet port 1010, diaphragm valve 1040 returns toapproximately its relaxed position, opening passage 1050 and allowingsimultaneous flow from first inlet port 1010 and second inlet port 1060to outlet port 1070. Because positive flow must be maintained, therecannot be upstream or backflow mixing (that is upstream of elastomericdisk 1020 into first inlet port 1010 and/or upstream of diaphragm valve1040 into second inlet port 1060). As the pressure drops in either thefirst inlet port 1010 or second inlet port 1060, the respective valveswill be closed.

FIGS. 11A-11E illustrate another embodiment of a valve system 1100 ofthe present invention that is operable to control the flow between twofluid reservoirs to an outlet port 1150 and therethrough to a patient. Afirst inlet port 1110 is connected to a first reservoir, while a secondinlet port 1120 is connected to a second reservoir, as described above.A valve body 1130 includes a tube valve member 1140 therein. Outlet port1150 delivers fluid from either or both of the inlet ports 1110, 1120 tothe patient. In FIG. 11A, the tube valve 1100 is in its normal state orflow condition in which fluid can flow from second inlet port 1120 tothe outlet port 1150 (or in the reverse direction, for example, for apatency check). First inlet port 1110 is blocked by flexible tube member1140, so there can be no backmixing into first inlet port 1110.

In FIG. 11B, the pressure in first inlet port 1110 is increased. At arelatively low pressure, a central, relatively thin-walled section 1142of tube valve member 1140 squeezes closed, blocking second inlet port1120. In the state illustrated in FIG. 11B, the pressure is not highenough to cause fluid from first inlet port 1110 to flow between thickerend section 1144 of tube valve member 1140 and an inner wall of valvebody 1130 to reach outlet port 1150.

In FIG. 11C, a slightly higher pressure in the first inlet port 1110causes relatively thicker section 1144 of tube valve member 1140 topartially collapse to provide an open volume between thicker section1144 and valve housing 1130 to allow flow from first inlet port 1110 tooutlet port 1150. In the state illustrated in FIG. 11C, second inletport 1120 remains blocked by fully collapsed central section 1142 oftube valve member 1140.

In FIG. 11D, both first inlet port 1110 and second inlet port 1120 arepressurized. In this state, flow through the tube valve 1100 from firstinlet port 1110 occurs as described above. However, the increase inpressure in second inlet port 1120 causes central section 1142 of tubevalve member to partially open to allow flow from second inlet port 1120to outlet port 1150, thereby allowing simultaneous flow from both inletports 1110 and 1120. If flow from either inlet ports 1110 or 1120 isceased, tube valve member 1140 closes the fluid path to the other inletport to prevent reverse mixing upstream.

The foregoing description and accompanying drawings set forth thepreferred embodiments of the invention at the present time. Variousmodifications, additions and alternative designs will, of course, becomeapparent to those skilled in the art in light of the foregoing teachingswithout departing from the scope of the invention. The scope of theinvention is indicated by the following claims rather than by theforegoing description. All changes and variations that fall within themeaning and range of equivalency of the claims are to be embraced withintheir scope.

1. A valve system for use in a system comprising a first source of afirst pressurized fluid and a second source of a second pressurizedfluid, the valve system comprising: a valve housing comprising a firstinlet port adapted to be placed in fluid connection with the firstsource, a second inlet port adapted to be placed in fluid connectionwith the second source and an outlet port; and a backflow preventionsystem to prevent flow of the first pressurized fluid through the secondinlet and to prevent flow of the second pressurized fluid through thefirst inlet port, wherein the valve system is adapted to provide a fluidpath between at least the first inlet port and the outlet port to enablefluid to be drawn from the outlet port to the first inlet port.
 2. Thevalve system of claim 1 wherein the backflow prevention system comprisesa first check valve in fluid connection with the first inlet port and asecond check valve in fluid connection with the second inlet port. 3.The valve system of claim 2 further comprising a bypass flow path todirect flow around the first check valve, thereby providing the fluidpath between the outlet port and the first inlet port to enable fluid tobe drawn from the outlet port to the first inlet port.
 4. The valvesystem of claim 3 wherein the backflow prevention system comprises asealing member movable within the valve housing in response to pressurechanges, the sealing member having a normal state in which it is biasedto block flow into the second inlet port, while a fluid path between thefirst inlet port and the outlet port is provided to enable fluid to bedrawn from the outlet port to the first inlet port.
 5. The valve systemof claim 4 wherein the at least one sealing member is biased by at leasta first spring.
 6. The valve system of claim 4 wherein the sealingmember comprises a piston member biased to abut a portion of the valvehousing to block flow into the second inlet port, the piston having apassage therethrough in fluid connection with the outlet.
 7. The valvesystem of claim 6 further comprising a valve housing member having apassage therethrough in fluid connection with the first inlet port, thefirst check valve being in fluid connection with the passage in thevalve housing member, the passage in the piston being in fluidconnection with the passage in the valve housing member, a fluid pathbeing provided around the housing member to provide the bypass flow pathin fluid connection with the passage in the piston and the first inletport when the piston is biased to abut the portion of the valve housing.8. The valve system of claim 7 wherein flow from the second fluid pathcauses the piston to move out of abutment with the portion of the valvehousing to provide a fluid connection between the second inlet port andthe outlet port, the piston being moved to abut the valve housing memberto block the bypass flow path, the passage in the piston remaining influid connection with the passage in the valve housing member.
 9. Thevalve system of claim 3 further comprising a bypass flow path to directflow around the second check valve, thereby providing a fluid pathbetween the outlet port and the second inlet port to enable fluid to bedrawn from the outlet port to the second inlet port.
 10. The valvesystem of claim 1 wherein the backflow prevention system comprises atleast a first sealing member movable within the valve housing inresponse to pressure changes.
 11. The valve system of claim 10 whereinthe first sealing member is biased to provide the fluid path between thefirst inlet port and the outlet port.
 12. The valve system of claim 10wherein the first sealing member is biased by a first spring.
 13. Thevalve system of claim 12 wherein flow from the second inlet port causesmovement of the first sealing member to block the fluid path between thefirst inlet port and the outlet port.
 14. The valve system of claim 13further comprising a second sealing member moveable within the valvehousing and a second spring positioned between the first sealing memberand the second sealing member, flow from the first inlet and concurrentflow from the second inlet causing the second spring to compress so thata fluid path is provided between the first inlet port and the outletport and a fluid path is provided between the second inlet port and theoutlet port.
 15. The valve system of claim 1 wherein the backflowprevention system comprises a deformable sealing member biased to blockflow into the second inlet port.
 16. The valve system of claim 15wherein flow of fluid into the second inlet port at a first pressuredeforms a first portion of the sealing member to block flow into thefirst inlet port.
 17. The valve system of claim 16 wherein flow of fluidinto the second inlet port at a second pressure higher than the firstpressure deforms a second portion of the sealing member to open a fluidpath between the second inlet port and the outlet port.
 18. The valvesystem of claim 17 wherein the valve housing comprises a first housingmember comprising the first inlet and a second housing member comprisingthe second inlet port, the first housing member and the second housingmember being attached to form the valve housing, the deformable sealingmember being positioned between the first housing member and the secondhousing member.
 19. The valve system of 17 wherein a fluid path isprovided between the first inlet port and the outlet port regardless ofa state of the deformable sealing member.
 20. The valve system of claim19 wherein flow into the first inlet port and concurrent flow into thesecond inlet port causes flow from the first inlet port into the outletport and concurrent flow from the second inlet port into the outletport.
 21. The valve system of claim 1 wherein the backflow preventionsystem comprises a flexible conduit positioned within the valve housingto block the second inlet port from being in fluid connection with theoutlet port, a passage through the conduit providing the fluid pathbetween the first inlet port and the outlet port to enable fluid to bedrawn from the outlet port to the first inlet port.
 22. The valve systemof claim 21 wherein an increase in pressure in the second inlet portcompresses a first portion of the flexible conduit to close the fluidpath between the first inlet port and the outlet port.
 23. The valvesystem of claim 22 wherein a further increase in pressure in the secondinlet port causes a second portion of the flexible conduit to compressto create a fluid path between the second inlet port and the outletport.
 24. The valve system of claim 1 providing for flow from the firstinlet port to the outlet port and concurrent flow from the second inletport to the outlet port.
 25. An injection system comprising: a firstsource of a first pressurized fluid; a second source of a secondpressurized fluid, and a valve system comprising: a valve housingcomprising a first inlet port in fluid connection with the first source,a second inlet port in fluid connection with the second source and anoutlet port; and a backflow prevention system to prevent flow of thefirst pressurized fluid through the second inlet and to prevent flow ofthe second pressurized fluid through the first inlet port, wherein thevalve system is adapted to provide a fluid path between at least thefirst inlet port and the outlet port to enable fluid to be drawn fromthe outlet port to the first inlet port.
 26. The injection system ofclaim 25 wherein the first source is a first syringe in fluid connectionwith a powered injector and the second source is a second syringe influid connection with the powered injector.
 27. A valve system for usein a system comprising a first source of a first pressurized fluid and asecond source of a second pressurized fluid, the valve systemcomprising: a valve housing comprising a first inlet port adapted to beplaced in fluid connection with the first source, a second inlet portadapted to be placed in fluid connection with the second source and anoutlet port; at least one deformable sealing member in operativeconnection with the first inlet port and the second inlet port, the atleast one deformable sealing member being biased to block flow into thesecond inlet port, and a fluid path between the first inlet port and theoutlet port regardless of a state of the at least one deformable sealingmember.
 28. The valve system of claim 27 wherein flow of fluid into thesecond inlet port at a first pressure deforms a central portion of thesealing member to block flow into the first inlet port.
 29. The valvesystem of claim 28 wherein flow of fluid into the second inlet port at asecond pressure, higher than the first pressure, deforms an outerportion of the sealing member to open a fluid path between the secondinlet port and the outlet port.
 30. The valve system of claim 29 whereinflow into the first inlet port and concurrent flow into the second inletport deforms the central portion of the deformable sealing member andcauses flow from the first inlet port into the outlet port andconcurrent flow from the second inlet port into the outlet port.
 31. Thevalve system for claim 29 wherein the valve housing comprises a firsthousing member comprising the first inlet and a second housing membercomprising the second inlet port, the first housing member and thesecond housing member being attached to form the valve housing, thedeformable sealing member being positioned between the first housingmember and the second housing member.
 32. The valve system for claim 29wherein the valve housing comprises a first housing member and a secondhousing member that are attachable to form the valve housing comprisingthe first inlet port, the second inlet port and the outlet port, thedeformable sealing member being positioned between the first housingmember and the second housing member.